This invention relates to an apparatus and method for detecting an object, and more specifically to detection of an object or series of objects that are residing upon a pallet.
Certain types of business applications use various versions of machine vision to assist in the processes of design, manufacture, and shipping of many types of products. Use of such machine vision devices are helpful in making all of those processes more efficient and accurate.
In recent years, automated devices have been found to be very effective in the shipping of products, and in the palletizing and depalletizing of various products during shipping. Utilization of various types of automated devices can result in very fast removal of objects from a pallet or in very fast stacking of objects onto a pallet for shipping. However, the efficiency of such automated devices can depend directly upon the proper execution of each step in the shipping process. For example, before a pallet of products can be shipped, the pallet should be checked to ensure that the pallet is full and that the objects placed upon the pallet have been properly placed. In like manner, a depalletizer that removes objects from a pallet needs an accurate location definition of the objects in order to position the picking end effecter of a robot for a successful pick and removing an object from a pallet. Thus, incorrect placement of objects on a pallet that has been loaded by automatic loading devices can result in damage to products, ineffective shipping, and reduced accuracy in the products being shipped, while incorrectly identifying the placement of objects on a surface can result in failure to remove objects from a pallet and in damage of the objects.
Prior art machine vision devices require consistent ambient lighting and in many cases it requires extra flood lighting in order to detect the variations between light and dark reflections. The rendered image from machine vision is also two dimensional and requires intense computation to figure out even low tolerance dimensions and locations. As a result, machine vision works best when interacting in real time with movements of the palletizer/depalletizer picking arm. This real time interaction usually requires the vision lens to be located near or even on the end effecter. The added task of providing a clear field of view with the mechanical equipment needed for picking being out of the way is often difficult.
Scanning and measuring with a remotely located laser measuring device(s) eliminates the need for lighting, end effecter lens mounting and real time interaction with the robot arm. It also provides the ability to adjust the placement of the layer as well as the picking via the use of a second layer measuring device if required.